Belt conveyor and auxiliary equipment thereof

ABSTRACT

Disclosed is a belt conveyor capable of greatly reducing friction resistance between side portions of a belt and troughs, comprising troughs ( 5 ), a belt moving above the troughs ( 5 ) along a longitudinal direction thereof, belt bending members ( 12 ) provided outside on both sides of the belt in the width direction so as to be located upstream of an entrance ( 5   a ) of the troughs, for abutting with both side portions of the belt to be bent upwardly, load cells ( 14 ) for detecting a reactive force exerted by the belt with which the belt bending members ( 12 ) make contact, guide rails ( 16 ) engaged to cause the belt bending members ( 12 ) to be displaced to be fixed at a desired position so as to bend the side portions of the belt or restore the bent belt, and rails ( 20 ) for moving the guide rails ( 16 ) along the longitudinal direction of the belt.

TECHNICAL FIELD

The present invention relates to a belt conveyor and associatedequipment. More particularly, the present invention relates to a beltconveyor provided with a carrying belt moving above troughs along theirlongitudinal direction, the troughs equipped on the belt conveyor,removers for removing residues of products adhering to the belt of thebelt conveyor, and loading devices for loading the products on variousconveyors.

BACKGROUND ART

FIG. 30 shows a conventional example of an air-cushion belt conveyorused in various industrial fields.

In the air-cushion belt conveyor (hereinafter simply referred to as abelt conveyor) 201, an endless belt (hereinafter simply referred to as abelt) 202 is installed around a pair of end pulleys 203, 204 provided atboth ends of the belt conveyor 201 with their axes horizontally placed.The pulleys 203, 204 rotate toward a direction indicated by an arrow Hin the Figure, thereby causing the belt 202 to circulate along adirection indicated by an arrow F. Troughs 205 (see FIG. 31) ofcircular-arc cross-section are provided close to the underside of a beltportion located on the upper side, i.e., forward (also referred to asoutward) belt.

The belt 202 is generally comprised of a core body made of cotton,vinylon, nylon, polyester, steel code and the like, and rubber coveringthe core body.

Between the end pulley 203 on a trough entrance side and an entrance 205a of the trough 205, upper-stage support roller trains 206 such astrough rollers, impact rollers, or the like for supporting the forwardbelt 202 from below, are arranged. Each of the upper-stage supportroller trains 206 forms a trough angle. Specifically, as shown in FIG.31( a), the upper support roller train 206 is configured such that aplurality of rollers 206 a are arranged in the shape of circular-arc tocause the belt 202 to be curved in the width direction as shown in FIG.31( a) to thereby allow curvature of cross-section of the belt 202 toconform to that of the troughs 205 (see FIG. 31( b)). Meanwhile, below abelt portion under the troughs 205, i.e., a return (also referred to ashomeward) belt, lower-stage support roller trains 207 comprised of flatrollers or the like for supporting the return belt portion to be flatare provided. In some cases, the lower-stage support roller trains 207on the return side are also configured such that a plurality of rollersare arranged in the shape of circular-arc similarly to the forwardtrains. The upper-stage support roller trains 206 and the lower-stagesupport roller trains 207 are arranged as being spaced along thelongitudinal direction of the belt 202.

As shown in a plan view of FIG. 32( a), the support rollers 206 a in therespective upper-stage support roller trains 206 are arranged in such amanner that gaps G between the rollers are arranged on straight lines asseen from the longitudinal direction of the belt. The support rollers207 a in the lower-stage support roller trains 207 are arranged in thesame manner, although this is not shown.

Therefore, the belt 202 is deformed by upward bending at positionscorresponding to the gaps G between rollers along the longitudinaldirection of the belt (see arrows in FIG. 32( b)). The deformation bybending is a characteristic in which once the belt is bent toward onedirection, the resistive force to the bending toward the same directionis reduced even after the belt is restored to its original shape afterthe corresponding bending force is released. On the other hand, theresistive force is increased when the belt is bent toward the oppositedirection to initial bending. This characteristic is believed to beattributed to visco-elasticity of rubber as a material of the belt 202.

Specifically, as shown in FIG. 32( b), the belt portion 202 on bothsides around the gap G between adjacent rollers (represented byreference numeral 206 a) as a center axis is upwardly bent. After thisbending is released and a belt shape is thereby restored, the beltportion tends to be easily bent upwardly.

As a result, when this portion of the belt 202 moves up onto the trough205, and is pushed up by compressed air, as shown in FIG. 32( c), thecross-section of the belt 202 in the width direction have corners Crather than smooth circular-arc (for easier understanding, the shape isexaggerated in the Figure). In order to prevent the corners C frommaking contact with the trough 205, it is necessary to increase an airpressure to thereby increase a floating force. This might cause anincrease in the amount of air escaping from the side portions of thebelt 202.

Meanwhile, between the end pulley 203 on the trough entrance side andthe entrance 205 a of the troughs 205, a shoot 208 is provided fordropping the products onto the belt 202. As shown in FIG. 31( a), thewidth of a lower end opening 208 a of the shoot 208, i.e., the dimensionof the lower end opening 208 a in the belt width direction is setslightly smaller than the width of the belt 202. This is because theexcess reduction of the width might cause the shoot 208 to get cloggedwith the products. Skirts 209 are provided on both sides of the belt 202in the width direction in the vicinity of where the shoot 208 isprovided, to prevent dropping of the products from the belt. The supportroller train 206 provided under the belt portion at a positioncorresponding to the position of the shoot 208 functions as impactrollers 206 for receiving drop load of the dropped products. The impactrollers 206 are, as described above, configured such that, the pluralityof rollers 206 a are arranged in the shape of circular-arc to cause thebelt 202 to be curved in the width direction to thereby allow curvatureof cross-section of the belt 202 to conform to that of the troughs 205(see FIG. 31( b)). A belt portion between the both end pulleys 203, 204is surrounded by a duct 210.

As shown in FIG. 31( b), an air-supply hole 211 is formed at the bottomof the trough 205. For the purpose of floating the belt 202 above thetrough 205, an air-supply device 212 is provided for injectingcompressed air into between the belt 202 and the trough 205 through theair-supply hole 211.

It is preferable that, in the belt conveyor, in particular in theair-cushion belt conveyor, the products are evenly loaded in right andleft direction with respect to a center portion on the belt portion inthe width direction. This is because if the products are unevenly loadedin the width direction of the belt, the belt is likely to snake becauseof directional imbalance between the floating force of air and thegravity of the products above the trough. However, in the belt conveyor201 provided with the shoot 208 having a large opening width, theproducts are unevenly arranged on the belt 202 depending on the state ofthe products dropping through the inside of the shoot 208, therebycausing the belt 202 to snake.

Accordingly, as a solution to this problem, belt conveyors have beenproposed as disclosed in Japanese Laid-Open Patent ApplicationPublication Nos. 7-125826, 9-169423. The belt conveyor comprises asensor for detecting snaking of the belt, and a mechanism for pivoting ashoot or a damper at a lower end of the shoot in the width direction ofthe belt. With such a configuration, a detection signal of the snakingdetection sensor is fed back to the shoot (damper) pivoting mechanism tochange the positions of the products being loaded toward the directionfor canceling the snaking. However, such a conveyor is complex inmechanism, and the number of parts is greatly increased.

In general, in the above-mentioned conveyor, when the belt 202 is curvedby the upper support roller trains 206 to cause the cross-section of thebelt 202 to conform in curvature to that of the trough 205, the belt isthereafter restored to a flat shape. As a result, when the belt 202moves up onto the trough 205, both side portions of the belt 202 arebrought into contact with the trough 205, and a space for compressed airfor air-cushion is ensured between the belt 202 and the trough 205.

However, in the case where the belt 202 is moving while its both sideportions are in sliding contact with the trough 205, friction resistancegenerated between the side portions of the belt and the trough becomeslarge and therefore is not negligible. As a result, it is necessary toselect a driver which outputs a high power for rotatably driving thepulleys 203, 204. Further, the friction between the side portions of thebelt 202 and the trough makes the life of the belt 202 shorter.

The trough of the air-cushion belt conveyor is provided with anextension/contraction allowance in the total length of the conveyor forabsorbing thermal expansion, manufacturing error, installation error,etc, which are associated with the troughs.

FIGS. 33( a), 33(b), and 33(c) are a plan view, a longitudinal sectionalview, and a side cross-sectional view, respectively, showing a generalconnecting method of the troughs. The air-cushion belt conveyor isconstituted such that air for air-cushion is supplied between thearc-shaped troughs 205 and the inwardly provided belt 202 from anair-supply chamber 213 under the trough 205 through the air-supply hole211, thereby causing the belt 202 to float and move. When the troughs205 form a long carrying path, a gap 214 is provided at the connectingportion between the troughs 205 as an extension/contraction allowance. Abacking plate (guide plate) 217 is provided between adjacent troughs205, for covering the gap 214, and a small air passage (groove) 218 isformed between the gap 214 between the troughs 205 and the surface ofthe backing plate 217.

For this reason, the air for air-cushion flowing between the belt 202and the troughs 205 flows outward in the width direction of the troughs205 along the air passage (groove) 218 and leaks outside at the sideportions. As a result, the belt 202 is floating unstably, whichincreases a moving resistance. It is therefore necessary to enhance acapability of a blower and thereby increase a supply amount of the airfor air-cushion.

Besides, when the troughs 205 are extended/contracted by heat or thelike, and in this state, the troughs 205 slide, this causes change inthe gap 214 between the trough 205, i.e., air passage (groove) 218; andhence change in leakage amount of the air for air-cushion leakingoutside through the air passage (groove) 218. This leads to unstableflotation of the belt 202, which is brought into contact with thetroughs 205, thereby resulting in an increase in a moving resistance.

Japanese Laid-Open Patent Application Publication No. Hei. 10-316244discloses a technique in which, for the purpose of simplifying aconnecting work of the troughs, a connecting guide member is protrudedby a predetermined amount from a rear end face of one of the troughs,the other trough is positioned on the upper side of a connecting guidemember, and bond is filled between end faces of these troughs. Thisprior art is disadvantageous in that the sliding of the troughextended/contracted due to heat is not permitted, although there are nogrooves through which the air for air-cushion escapes.

The products adhere to the belt 202 and such residues are carried alongwith movement of the belt 202. Then, they drop, fly, or adhere around areturn belt moving path, thereby causing contamination, corrosion,deposition, or change in moving resistance.

Accordingly, there has been conventionally proposed a device forremoving residues on the belt on the return side. The residue removingmeans includes scraping by cleaners, or cutwater rollers (the rolleradapted to press against the belt).

Publication of Unexamined Patent Application Publication No. Hei.7-20767 discloses a blade constituting a scraper, which is mounted toextend in the width direction of the belt and to be adjustablypositioned by rotation around an axis extending in the width directionof the belt. The blade is curved as having a distance from the axisincreasing from both sides of the belt toward its center portion as seenfrom the width direction of the belt. When the blade rotates around theaxis and its center portion in the width direction rises up with respectto the belt, this becomes an arch-shaped scraping portion for the belt.In accordance with this, even when the belt is deformed by the troughsin the shape of arch, i.e., deformed by bending, the scraping portioncan be made into contact with the belt surface without gap between thescraping portion of the belt and the belt surface. As a result, theresidues on the belt surface can be suitably scraped.

Japanese Laid-Open Patent Application Publication No. Hei. 6-271045discloses that first to third processing rollers are rotatably providedin the vicinity of a terminal end portion of the belt conveyor, forguiding the belt inverted at the terminal end portion to snake. Inaccordance with this, while the belt inverted at the terminal endportion of the belt conveyor snakes through the first to thirdprocessing roller, the residues are pressed between the belt and thefirst processing roller into dehydrated and layered pieces, which arebent and cracked by the processing rollers, and the resulting layeredbroken pieces can be scraped and removed from the belt surface bybringing the third processing roller into contact with the belt.

Meanwhile, the belt is deformed by bending by the support roller trains.This is because, the cross-section of the belt is supported to bearch-shaped by the guide rollers having the trough angles as describedabove, for stably loading the products on the forward belt movingoutward with the products loaded thereon.

Since each of the above means is adapted to remove the residues whilekeeping the cross-section of the belt in the shape of a straight line,the residue removing capability is high at the center portion of thebelt but is low at the belt side portions due to the deformation bybending of the belt and reduction of the pressing force. In general,since the residues are less at the belt side portions than at the centerportion, attention has been hardly focused on removal of the residues atthe belt side portions. Under the circumstances, effective removingmeans has not been proposed.

DISCLOSURE OF THE INVENTION

The present invention is directed to solving the problem, and an objectof the present invention is to provide a belt conveyor capable ofobtaining sufficient air-cushion amount without increasing an airpressure by preventing occurrence of deformation of a belt by bending.

Another object of the present invention is to provide a conveyor capableof preventing uneven distribution of products and thereby preventingsnaking of the belt, and a loading device used in the conveyor and aguide member therefor with a simple configuration.

Another object of the present invention is to provide a belt conveyorcapable of significantly reducing friction resistance between sideportions of the belt and a trough while ensuring a space of compressedair for air-cushion between the belt and the trough.

Another object of the present invention is to provide a trough of anair-cushion belt conveyor in which leakage of the air for air-cushionfrom a connecting portion between the troughs hardly occurs so thatstable flotation and movement of the belt are reliably performed.

In addition, another object of the present invention is to provide ameans for improving residue removing capability at side portions of theconveyor belt.

To solve the above-described problems, according to the presentinvention, there is provided a trough of an air-cushion belt conveyor,the belt conveyor being provided with interconnected troughs,characterized in that the troughs have a sliding structure with a gapbetween the troughs so as to be slidable in their longitudinaldirection, and a seal mechanism capable of preventing leakage of air forair-cushion regardless of change in the gap due to sliding of the troughis provided at a connecting portion between the troughs.

With such a configuration, since leakage of the air for air-cushion isprevented during sliding of the trough, the amount of air supply can bereduced. Also, the flotation above the troughs stably occurs withoutinsufficient supply of air for air-cushion at the connecting portionbetween the troughs, and the moving resistance can be reduced.

A trough of an air-cushion belt conveyor, the belt conveyor beingprovided with interconnected troughs, is characterized in that thetroughs have a sliding structure with a gap between the troughs so as tobe slidable in their longitudinal direction, and a labyrinth sealmechanism capable of preventing change in leakage amount of air forair-cushion regardless of change in the gap due to sliding of the troughis provided at the connecting portion between the troughs.

Thereby, since the amount of air supply can be reduced and the leakageamount of the air for air-cushion can be stabilized, the belt can floatstably and the moving resistance can be reduced.

In this case, it is preferable that at the connecting portion betweenthe troughs of the air-cushion belt conveyor, the troughs are fitted attheir concave and convex portions with a gap in a direction in which thetrough slides, thereby forming the sliding structure, and minute gapsparallel to the direction in which the trough slides are created duringsliding of the trough, thereby forming the labyrinth seal mechanism.Since the provision of the labyrinth seal structure at the troughconnecting portion can make the width of an air passage in a labyrinthportion constant regardless of change in the gap between the troughs,and hence, the leakage amount of the air for air-cushion can be madeconstant. As a result, floatation of the belt can be stabilized.

The minute gaps constituting part of the labyrinth seal mechanism areprovided inwardly of belt side portions. Thereby, leakage of the air forair-cushion can be reliably prevented and the leakage amount of the airfor air-cushion does not vary even during sliding of the trough.

When the sliding structure having the seal mechanism or the labyrinthseal mechanism is provided in multiple stages in the longitudinaldirection of the troughs, the sliding amount of the trough can beincreased. This makes it possible to absorb a large sliding amountoccurring in the conveyor having a long carrying path.

In the above configuration, a guide plate may be provided at theconnecting portion between the troughs, for guiding movement of thetrough, and may be provided with an air-supply chamber for supplying airfor air-cushion and an air-supply hole through which a gap forpermitting sliding communicates with the air-supply chamber. This makesit possible that the air for air-cushion can be sufficiently ensured atthe connecting portion between the troughs, and the corresponding beltportion stably floats.

The guide plate is fixed to one of the troughs, and the other trough isslidably engaged with the guide plate through an elongated hole or alarge-diameter hole provided in the guide plate. This enables smoothsliding of the trough.

According to the present invention, there is provided a device forremoving residues adhering to belt side portions on a return side of aconveyor belt, characterized in that cutwater rollers or scrapers areadapted to be pressed against the belt side portions to be bent towardan opposite direction to bending of the belt deformed by the bending ona forward side of the conveyor belt.

By removing the residues only at the belt side portions independently,the removal of the residues can be effectively accomplished withoutbeing affected by the deformation of the belt by bending and reductionof the pressing force. In addition, since the cutwater and scraping atthe belt side portions in the width direction can be reliably performed,dropping water or powder receivers (hereinafter referred to as “waterreceivers”) are installed only at the center portion of the belt in thewidth direction under the conveyor.

By arranging the cutwater rollers and the scrapers along a direction inwhich the belt moves, the removal of the residues at the belt sideportions can be reliably performed.

When the belt on the return side has trough shape, the cutwater rollersor scrapers are adapted to be pressed against the belt side portions forpushing the belt side portions inwardly more than the trough shape tocause the belt side portions to be greatly bent. Thereby, the removal ofthe resides on the belt side portions can be effectively performedwithout reduction of the pressing force.

In this case, by arranging the cutwater rollers and the scrapers alongthe direction in which the belt moves, the removal of the residues atthe belt side portions can be more reliably performed.

In the above configuration, water receivers are provided at a centerportion of the belt over an entire conveyor. This achieves a simplifiedapparatus in a narrow space. Also, by providing straight-line shapedpress rollers or belt cleaners in a width direction of the belt so as tobe located downstream of the cutwater rollers or the scrapers in thedirection in which the belt moves, the residues adhering to the centerportion of the belt can be also removed, so that the residue removingcapability is exhibited over the entire width of the belt.

According to the present invention, there is provided a guide member fora loading device, the guide member being placed at a lower end of ashoot provided above a carrying path of a conveyor and adapted to guideproducts onto a belt, the guide member comprising: a bottom plateprovided as being inclined downwardly and forwardly and having a widthdecreasing toward its front, and side plates provided along both sidesof the bottom plate.

According to the guide member, most of the products are loaded on thecarrying path such as the belt from a front edge of the bottom platehaving small width. Therefore, most of the products are gathered to thecenter portion in the width direction of the belt and evenly distributedin the lateral direction from the center portion as a crest of mountain.It should be appreciated that the guide member is located at the lowerend of the shoot, although this may be installed at the lower end.

In the guide member, the both side plates extend outwardly and upwardly.Thereby, even the products dropping through the inside of the shoot in adispersed state, are gathered naturally to the center portion by theboth side plates.

The bottom plate and the side plates are continuously and integrallycurved with a circular-arc-shaped horizontal cross-section having anaverage curvature increasing toward a carrying path face. Thisconfiguration is applicable to shoots of a circular cross-section or ofan elliptical cross-section.

According to the present invention, there is provided a loading devicefor a belt conveyor, the loading device being adapted to load productson a carrying path of a conveyor, comprising: a shoot constituting apath through which the products drop; and one of the above-mentionedguide members provided to be located at a lower end of the shoot.

The loading device provides function and effects of the guide member ofthe present invention.

The both side plates of the guide member are mounted to a rear portionof both sides of an opening formed at the lower end of the shoot.Thereby, in addition to a front opening of the guide member, a frontportion of the opening in the lower end of the shoot serves as an exitof the products from the shoot. Therefore, the shoot does not getclogged even when a great many products are dropping.

Also, a plurality of guide members are provided along a front and reardirection of the opening formed at the lower end of the shoot. Even whena great many products are dropping or the products are dropping throughthe inside of the shoot in a dispersed state, they are gatherednaturally to the center portion of the carrying path by all the guidemembers.

The guide member is movably provided along the front and rear directionof the opening formed at the lower end of the shoot and is adapted to befixed at a desired position. This allows the guide member to beadjustably positioned in the front and rear direction. Therefore, theguide member can be installed at the position where many of the productsbeing dispersed and dropping through the inside of the shoot aregathered or many of the products dropping through the inside aregathered depending on an operation state.

According to the present invention, there is provided a conveyorcomprising: a long carrying path moving with products loaded thereon;and one of the above-mentioned loading devices, provided above thecarrying path, for loading the products on the carrying path.

In accordance with the conveyor, the snaking of the carrying path can beprovided without a need to provide a complex mechanism such as a snakingdetector of the belt or a pivoting device of the shoot, unlike theconventional conveyor.

In the conveyor, skirt members are vertically provided on both right andleft sides of the carrying path over a front and rear range in which theloading device is located, and an upper end of the guide member islocated below upper ends of the skirt members. This prevents lateraldropping of the products can be prevented. Also, the guide member can bemounted to the skirts.

As defined herein, “forward” in claims refers to the direction in whichthe belt moves and “rearward” in claims refers to its oppositedirection.

According to the present invention, there is provided a belt conveyorcomprising: troughs; a belt moving above the troughs along alongitudinal direction of the troughs; and belt bending members providedupstream of an entrance of the troughs such that the members are placedoutside on both sides in a width direction of the belt, wherein the beltbending members are adapted to abut with both side portions of the beltto be upwardly bent (including bending toward the center of the belt inthe width direction).

In accordance with the belt conveyor, since the both side portions ofthe belt are temporarily upwardly bent, these side portions of the beltare deformed by upward bending. That is, even after the belt shape isrestored after the bending is released, the belt is easily bentupwardly. In other words, the belt has resistance force to upwardbending less than that of an unbent belt. As a result, when the beltmoves up onto the belt and the both side portions of the belt makecontact with the trough, the friction resistance to the movement of thebelt from the trough is reduced and a power of a driving source can belessened. Thereby, equipment cost and operation cost can be reduced andthe life of the belt can be prolonged.

As defined herein, based on the movement of the belt, “upstream” inClaims refers to an opposite side of downstream toward which the beltmoves.

It is preferable that in the above belt conveyor, the belt bendingmember is adapted to move along a longitudinal direction of the belt soas to be close to or away from an entrance of the troughs and to befixed at a desired position for the reason described below.Specifically, the circulating belt is bent and then the shape of thebent portion is gradually restored. It is preferable that when the beltmoves up onto the trough, the belt is restored to substantially conformin shape to the cross-section of the trough. In accordance with theabove constitution, for achieving desirable restoration at the entranceof the trough, the set position of the belt bending member can beadjusted at a proper distance from the entrance of the trough.

It is preferable that the belt bending member of the belt conveyor iscomprised of rollers provided so as to be rotated by side portions ofthe moving belt, because resistance to the circulating belt is less.

It is preferable that the belt bending member of the conveyor belt iscomprised of sliding members with which side portions of the moving beltare in sliding contact. This is because resistance to the belt is lesssimilarly to the rollers, and maintenance becomes easy.

It is preferable that the belt conveyor further comprises first reactiveforce detectors for detecting a reactive force exerted by the belt withwhich the belt bending members abut. This is because the bending degreeof minimizing moving resistance of the belt exerted by the trough andthe reactive force from the belt can be detected and managed asparameters.

In the belt conveyor comprising second reactive force detectors providedindependently of and apart from the belt bending members, for detectinga reactive force exerted by the belt in a state in which the beltbending members are in contact with the side portions of the belt, thebending degree of minimizing the moving resistance of the belt exertedby the trough can be known as well.

It is preferable that in the belt conveyor, the belt bending member isadapted to be displaced and fixed at a desired position to cause theside portions of the belt to be bent or the bent belt to be restored.This is because by displacing the belt bending member toward the abovedirection, desirable bending degree of the side portion of the belt canbe selected. The desirable bending degree is bending which causesdeformation minimizing resistance exerted by the trough.

It is preferable that the belt conveyor further comprises displacingdevices for displacing the belt bending members to cause the sideportions of the belt to be bent or the bent belt to be restored, whereinthe displacing device is adapted to fix the belt bending member at adisplaced desired position. Conveniently, the operation of thedisplacing devices eliminates the need for an operator to cause the beltbending member to move and fix the same according to displacementdegree. The displacing device includes, an air cylinder, a hydrauliccylinder, a servo motor, ball screws, etc.

It is preferable that the belt conveyor comprises one of the firstreactive force detectors and the second reactive force detectors, andthe above-mentioned displacing devices, wherein the displacing device isadapted to displace the belt bending member according to a reactiveforce value detected by the one of the reactive force detectors, becauseeffective bending can be automatically given to the belt.

According to the present invention, there is provided an air-cushionbelt conveyor comprising: troughs; a belt caused to float above thetroughs and move along a longitudinal direction of the troughs; andfirst support members provided outside of the troughs to support thebelt from below, wherein a plurality of first support members arearranged as being spaced apart from each other along a longitudinaldirection of the belt, each of the first support members comprises aplurality of support elements arranged in a width direction of the belt,and at least adjacent first support members are configured such thatgaps between support elements are arranged so as not to be on straightlines as seen from the longitudinal direction of the belt.

In accordance with the belt conveyor, since the deformation of the beltby bending is unbent by the support member placed adjacently, influenceof deformation by bending can be substantially eliminated and occurrenceof corners of the belt being floated up can be suppressed.

It is preferable that in the belt conveyor, gaps between supportelements in one first support member of all the first support membersare arranged so as not to be on the same straight lines as gaps betweensupport elements in the other first support members. Thereby, thedeformation by bending is further reduced and points of the deformationby bending in the width direction of the belt are increased, so thatcorners are not formed in the belt.

It is preferable that the support elements are comprised of rollersattached rotatably around an axis in a width direction of the belt,because the resistance to the circulating belt is less.

It is preferable that the support elements are comprised of slidingmembers, because maintenance becomes easy because of absence of movingparts.

Or, one part of the support elements constituting all the first supportmembers may be comprised of the rollers and the other part may becomprised of sliding members. That is, the rollers and the slidingmembers may coexist in the entire first support member. The rollers andthe sliding members may be arranged at desired positions.

According to the present invention, there is provided an air-cushionbelt conveyor comprising: troughs; a belt caused to float above thetroughs and move along a longitudinal direction of the troughs; andsecond support members provided outside of the troughs to support thebelt from below, wherein the second support members are comprised ofsliding members extending continuously along a width direction of thebelt.

In accordance with the belt conveyor, the deformation of the belt bybending can be prevented because of absence of the gaps.

In the belt conveyor, a plurality of second support members may bearranged as being spaced apart from each other along the longitudinaldirection of the belt.

The air-cushion belt conveyor having the second support members mayfurther comprise first support members provided outside of the troughs,for supporting the belt from below, the first support members beingcomprised of a plurality of support elements arranged in the widthdirection of the belt. Thereby, the deformation of the belt by bendingcan be effectively prevented.

In the air-cushion belt conveyor having the second support members, inwhich one of the second support members is provided in contact with anend portion of the trough, the second support member provides functionfor closing a space between the trough and the belt, escape of acompressed gas in this space can be suppressed. As a result, effectivebelt flotation can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an entrance-side pulley according to anembodiment of a belt conveyor of the present invention and its vicinity;

FIG. 2( a) is a cross-sectional view taken along line IIA—IIA in FIG. 1and FIG. 2( b) is a plan view of FIG. 2( a);

FIG. 3 is a perspective view showing a mechanism for moving an abuttingroller and a reactive force detector in the belt conveyor in FIG. 1;

FIG. 4 is a side view showing another embodiment of the belt conveyor ofthe present invention;

FIG. 5( a) is a perspective view showing another example of a beltbending member in the belt conveyor in FIG. 1 and FIG. 5( b) is apartially cutaway perspective view showing another example of the beltbending member;

FIG. 6 is a view showing a principle according to the present inventionfor improving a residue removing capability at belt side portions;

FIG. 7 is a view showing another principle according to the presentinvention for improving the residue removing capability at the belt sideportions;

FIG. 8( a) is a front view showing a state in which the belt sideportions are bent further inwardly by cutwater rollers than theconventional belt portion in trough shape when a return belt has troughshape, and FIG. 8( b) is a side view;

FIG. 9 is a front view showing a state in which the belt side portionsare further inwardly bent by scrapers;

FIG. 10 is a side view showing an end portion of an air-cushion beltconveyor to which the present invention is applied;

FIG. 11 is a perspective view showing main part of a residue removingmeans according to the present invention which is installed on theair-cushion belt conveyor;

FIG. 12 is a front view showing the residue removing means in FIG. 11;

FIG. 13 is a plan view showing the residue removing means in FIG. 11;

FIG. 14 is a plan view in the direction of arrows taken along lineXIV—XIV in FIG. 1;

FIG. 15( a) is a cross-sectional view taken along line XVA—XVA in FIG.14 and FIG. 15( b) is a cross-sectional view taken along line XVB—XVB inFIG. 14;

FIG. 16 is a plan view showing main part of another embodiment of thebelt conveyor of the present invention;

FIG. 17( a) is a plan view showing main part according to anotherembodiment of the belt conveyor of the present invention, FIG. 17( b) isa cross-sectional view taken along line XVIIB—XVIIB in FIG. 17( a), andFIG. 17( c) is a view taken in the direction of arrows along lineXVIIC—XVIIC in FIG. 17( a);

FIG. 18( a) is a plan view showing main part according to anotherembodiment of the belt conveyor of the present invention, FIG. 18( b) isa cross-sectional view taken along line XVIIIB—XVIIIB in FIG. 18( a),FIG. 18( c) is a cross-sectional view taken in the direction of arrowsalong line XVIIIC—XVIIIC in FIG. 18( a), and FIG. 18( d) is a view takenin the direction of arrows XVIIID—XVIIID in FIG. 18( a);

FIG. 19( a) is a plan view showing main part according to anotherembodiment of the belt conveyor of the present invention, and FIG. 19(b) is a partially broken cross-sectional view taken in the directionalong line XIXB—XIXB in FIG. 19( a);

FIG. 20 is a schematic view showing an example of the air-cushionconveyor to which the present invention is applied;

FIG. 21( a) is a plan view of a connecting portion of a slidingstructure including a labyrinth seal structure of the present invention,FIG. 21( b) is a longitudinal sectional view showing a portion where anair-supply chamber is located, and FIG. 21( c) is a side cross-sectionalview;

FIG. 22( a) is a side cross-sectional view showing a state in which theair-supply chamber is provided in a guide plate, and FIG. 22( b) is arear view thereof;

FIG. 23( a) is a cross-sectional view showing an example of a stud boltin a state in which a trough and a guide plate are slidably engagedthrough an elongated hole or the like, and FIG. 23( b) is across-sectional view showing main part showing an example of a flushbolt;

FIG. 24( a) is a side cross-sectional view showing an example in whichthe connecting portion of the sliding structure having the labyrinthmechanism is set in multi stages for increasing a sliding amount of thetrough and FIG. 24( b) is a rear view thereof;

FIG. 25 is a perspective view showing a guide member in FIG. 1;

FIG. 26( a) is a side view showing a state in which products aretraveling through a loading device in FIG. 1, FIG. 26( b) is across-sectional view taken along line XXVIB—XXVIB in FIG. 26( a),showing an inside of a shoot, FIG. 26( c) is a cross-sectional viewtaken along line XXVIC—XXVIC, showing an inside of the guide member, andFIG. 26( d) is a cross-sectional view taken along line XXVID—XXVID,showing above of the belt;

FIG. 27( a) is a front view showing another embodiment of the loadingdevice of the present invention, FIG. 27( b) is a plan view thereof, andFIG. 27( c) is a side view thereof;

FIG. 28 is a side view showing another embodiment of the loading deviceof the present invention;

FIG. 29 is a perspective view showing another embodiment of the loadingdevice of the present invention;

FIG. 30 is a side view showing an example of the conventional beltconveyor;

FIG. 31( a) is a cross-sectional view taken along line XXXIA—XXXIA inFIG. 30 and FIG. 31( b) is a cross-sectional view taken along lineXXXIB—XXXIB in FIG. 30;

FIG. 32( a) is a view taken in the direction of arrows along lineXXXIIA—XXXIIA in FIG. 30, FIG. 32( b) is a view taken in the directionof arrows along line XXXIIB—XXXIIB in FIG. 30, and FIG. 32( c) is across-sectional view schematically showing a state of the belt on thetroughs; and

FIG. 33( a) is a plan view showing an example of a connecting portionbetween the conventional troughs, FIG. 33( b) is a longitudinalsectional view thereof, and FIG. 33( c) is a side cross-sectional viewthereof.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of a belt conveyor and its associatedequipment of the present invention will be described with reference tothe accompanying drawings.

A belt conveyor 1 shown in FIGS. 1 and 2 has an entire configurationsimilar to that of the conventional air-cushion belt conveyor 201 shownin FIGS. 30 and 31. There is also provided an air-supply hole and anair-supply device for injecting compressed air between a conveyor belt(hereinafter simply referred to as a belt) and a trough 5 through theair-supply hole, although these are not shown. A first differencebetween the belt conveyor 1 and the conventional belt conveyor 201 isthat a belt bending member 12 and a reactive force detector are providedon outside of each of both sides of the belt 2 in the width direction,between an entrance-side end pulley 3 and an entrance 5 a of the troughs5. A second difference is that a removing mechanism for removingresidues adhering to the belt is provided on a return side of the belt.A third difference is a structure of a support member train (forexample, roller train or slide member train) as a first support member,and a structure of a support slide member as a second support member. Afourth difference is a mechanism of a connecting portion betweentroughs. A fifth difference is that guide members 103, 115 for theproducts are provided at a position of a lower end of a shoot 8. Shoots8, 102, 114 and the guide members 103, 115 constitute loading devices101, 111, 113. Therefore, the same components as those of the beltconveyor 201 in FIGS. 30 and 31 and the corresponding functions will notbe further described.

The belt bending members 12 are adapted to press both side portions ofthe belt 2 to be inwardly (upwardly) bent, thereby giving deformation bybending to the belt 2. The deformation by bending of the belt 2 is thatonce the belt is bent toward a direction, a resistive force to bendingtoward the same direction is reduced even after the belt 2 is restoredto its initial shape (in general, flat). On the other hand, when thebelt 2 is bent toward the opposite direction to the direction in whichthe belt is initially bent, the resistive force is increased. Thischaracteristic is believed to be attributed to visco-elasticity ofrubber as a material of the belt 2.

If the both side portions of the belt 2 are temporarily inwardly bentbefore the belt 2 enters the trough 5, utilizing this characteristic,then resistive force of the both side portions of the belt 2 in contactwith the trough 5 with respect to inward bending is reduced even afterits shape is restored, so that the belt 2 is easily bent inwardly. As aresult, by action of the compressed air between the trough 5 and thebelt 2 as well as the above characteristic, the friction resistance tothe movement of the belt 2 is reduced, and a power of a drive source islessened. This leads to reduced equipment cost and operation cost. Also,the life of the belt 2 can be prolonged.

The belt bending members 12 shown in FIGS. 1 and 2 are each constitutedby an abutting roller 13 which abuts with a side of the belt 2. Theabutting roller 13 is rotatably attached to a lever 14 a of a knownlever type load cell (hereinafter simply referred to as a load cell) 14as a first reactive force detector. The load cell 14 is mounted to amounting bracket 15. Guide rails 16 are installed in the width directionof the belt. The bracket 15 is engaged with the guide rail 16 so as tobe movable close to or away from the side portion of the belt 2. Theguide rails 16 are each provided with an air cylinder 17 as a displacingdevice in the vicinity of an outer end thereof as an end portion on theopposite side of the belt, and a tip end of a piston rod 17 a of the aircylinder 17 is fixed to the bracket 15. The air cylinder 17 causes thebracket 15, and consequently, the abutting roller 13 to move close to oraway from the side portion of the belt 2. The air cylinder may bereplaced by a hydraulic cylinder, or otherwise a servo motor and ballscrews or the like. Although the guide rails 16 are installed under theforward belt 2 a, they are not intended to be limited to thisconfiguration, but may be installed above the belt, i.e., on a ceilingside, and the bracket may be movably suspended.

In accordance with this configuration, the air cylinder 17 causes theabutting roller 13 to advance to thereby press the side portion of thebelt 2 to be inwardly bent. In this case, the pressing force can beadjusted or released by advancement/retraction of the roller 13. Whenthe abutting roller 13 presses the side portion of the belt 2 to bebent, the load cell 14 detects a reactive force exerted by the belt.

A control device 19 is connected to an air-supply source 18 of the loadcell 14 and the air cylinder 17. According to a reactive force valuedetected by the load cell 14, the control device 19 controls the amountof compressed air to be supplied to the air cylinder 17, therebyadjusting the pressing force to the belt 2 by the butting roller 13.This configuration allows the pressing force to the belt by the abuttingroller 13 to be automatically adjusted to be in a predetermined properpressing force range. The proper pressing force range can be known whentest operation of the belt conveyor 1 is carried out. One standard is adriving force (power consumption or the like of the driving source) forcirculating the belt.

In the above embodiments, the air cylinder 17 is used to cause theabutting roller 13 to move in straight line so that the pressing forceto the belt by the abutting roller 13 is changed, but this configurationis only illustrative.

For example, the load cell 14 is rotatably mounted to the bracket 15.Then, a body of the load cell 14 is rotated to be fixed at a desiredangle of the lever 14 a around the body. To be specific, a cylindricalclamp which is not shown is fixed to the bracket 15, and the body of theload cell is inserted into the clamp, to be clamped and fixed. In orderto rotatably displace the load cell, the clamp is loosened. This canvary bending amount, although the direction toward which the sideportion of the belt is bent is varied. Alternatively, the rotationaldisplacement and the straight-line displacement may be combined.

As shown in FIGS. 1 and 3, from a vicinity of the entrance-side pulley 3to a vicinity of the entrance 5 a of the trough on both sides of thebelt conveyor 1, rails 20 are installed in parallel with thelongitudinal direction of the belt 2. The rails 20 may be provided on aninner surface, an outer surface or the like of the duct 10. The guiderails 16 are movably engaged with the rails 20 and fixed at a desiredposition on the rails 20. Therefore, the abutting rollers 13 are capableof pressing the side portions of the belt to be bent at a desiredposition in a range from the vicinity of the entrance-side pulley 3 tothe entrance 5 a of the trough. The movement of the guide rails 16 isachieved by rotating ball screws which are not shown by using a motorwhich is not shown, or otherwise by an operator. When the guide rail 16moves, the air cylinder 17 causes the abutting roller 13 to retractunder control of the control device 19. Thereafter, under control of thecontrol device 19, the ball screw rotates to cause the guide rail 16 tomove. The guide rails 16 are placed so as not to interfere with theupper support roller trains 6, i.e., below or outside of the uppersupport roller trains 6.

The circulating belt 2 is bent by the abutting rollers 13 andthereafter, the shape of the bent portion is gradually restored. It isdesirable that when the belt 2 enters the trough 5, the shape berestored so as to substantially conform to a curvature of a circular-arccross-section of the trough 5. In accordance with the configuration, theset position of the abutting rollers 13 can be adjusted to be properlydistant from the entrance 5 a of the trough to achieve desirablerestoration at the entrance 5 a of the trough. The proper distance canbe known when the test operation of the belt conveyor 1 is carried out.One standard is a driving force (power consumption or the like of thedriving source) for circulating the belt.

In the above embodiment, the load cell 14 as the first reactive forcedetector is provided to function through the abutting roller 13. But,the present invention is not limited to this configuration. For example,the abutting roller 13 may be rotatably mounted to the mounting bracketwithout the load cell 14 and second reactive force detectors may beprovided to abut with side portions of the belt at another position.

FIG. 4 shows such a belt conveyor 21. In the belt conveyor 21, loadcells 22 as the second reactive force detectors are provided in thevicinity of an exit 5 b of the trough so as to be in contact with thebelt 2 exiting from the exit 5 b. That is, the load cells 22 areprovided independently of the abutting rollers 13.

And, the control device 19 (FIG. 2( a)) connected to the air-supplysource 18 of the load cell 22 and the air cylinder 17 is adapted tocontrol the amount of compressed air to be supplied to the air cylinder17 according to the reactive force value detected by the load cell 22,thereby adjusting the pressing force to the belt 2 by the abuttingroller 13. The resistance force to bending of the belt 2 at the exit 5 bof the trough is fed back to allow the pressing force to the belt by theabutting roller to be automatically adjusted to be in a proper pressingforce range. The proper pressing force range can be known when the testoperation of the belt conveyor 1 is carried out. One standard is adriving force (power consumption or the like of the driving source) forcirculating the belt.

The mounting position of the load cells 22 as the second reactive forcedetectors is not limited to the vicinity of the exit of the trough 5.For example, the load cells 22 may be mounted in the vicinity of theentrance 5 a of the trough. In brief, the load cells 22 are provided soas to abut with the belt 2 independently of the abutting rollers 13.

While in the above embodiment, the rotatable rollers are used as thebelt bending members, the bending members are not limited to the rollersin the present invention. For example, a sliding member made ofsynthetic resin or the like that has low friction coefficient and wearresistance, such as super-polymer polyethylene may be used. The shape ofthe sliding member can be selected from various shapes. For example, asshown in FIG. 5( a), a cylindrically molded sliding member 23 may beused. As shown in FIG. 5( a), the cylindrical sliding member 23 ismounted such that upper and lower ends thereof are removably attached toa U-shaped holder 24 by means of a bolt 25 or the like, andapproximately at a right angle with respect to the side portion of thebelt. Or, another known method may be employed. Alternatively, as shownin FIG. 5( b), a partially cylindrical sliding member 27 may be mountedso as to conform to a belt-side face of a partially cylindrical bracket26 made of metal or synthetic resin. It is preferable to use a flushscrew 28 when mounting the sliding member 27 to the bracket 26, becausea head of the screw is not exposed from the sliding member 27.

In the above embodiment, the belt bending members and the reactive forcedetectors are provided for the forward belt, i.e., the upper belt movingto the left in FIG. 1. Alternatively, they may be provided for thereturn belt, i.e., the lower belt moving to the right in FIG. 1. This isbecause if the troughs are provided for the return belt, then thefriction resistance to the belt is effectively reduced by providing thebelt bending members and the reactive force detectors.

FIGS. 6 and 7 show principles according to the present invention, forimproving residue removing capability at belt side portions. In theseFigures, part of the return-side belt is partially shown.

FIG. 6 shows that cutwater rollers 30 are adapted to press against sideportions 2 c of the belt 2 on the return side of the belt 2. Thecutwater roller 30 is provided to push up the side portion 2 c of thebelt by a constant pressing force such that its axis 32 is directedobliquely, i.e., in the direction orthogonal to the direction in whichthe belt moves as seen in a plan view (direction orthogonal to a cutawaysurface of the Figure). The cutwater roller 30 is rotatable around theaxis 32 with movement of the belt 2 in contact with the cutwater roller30.

The cutwater roller 30 presses against the side portion 2 c of the beltto be supported in a bent state. The side portion 2 c of the belt isbent toward the opposite direction to the direction toward which thecenter portion of the outward (forward) belt is bent and deformed inU-shape because the forward belt is supported in the configuration oftrough. By bending the belt toward the opposite side, the cutwaterrollers 30 can be reliably pressed against the side portion 2 c of thebelt without a decrease in the pressing force, and scraping of theresidues adhering to the side portion 2 c of the belt is facilitated.The scraped and dropping products or water is up onto a dropping orpowder receiver (water receiver) 36.

FIG. 7 shows that the cutwater rollers 30 are replaced by cleaners 34provided at both side portions of the belt 2. The cleaners 34 are eachconfigured such that a plate-shaped scraper 35 is attached to an upperend portion of a holding member 33. The scraper 35 is pushed up againstthe belt 2 from below, thereby allowing the side portion 2 c of the beltto be bent toward the opposite direction to the deformation by bendingas described above.

Only the cutwater rollers 30 or the scrapers 34 may be provided, or thecutwater rollers 30 and the scarpers 34 may be arranged along thedirection in which the belt moves, so that the residues adhering to theside portion 2 c of the belt can be effectively removed.

In the above example, the return belt is flat. As shown in FIGS. 8( a)and 8(b), when the return belt 2 has trough shape, the side portion 2 cof the belt is inwardly bent more than that of normal trough shape(shape having a certain curvature radius as indicated by an imaginaryline in FIG. 8( a)) so as to be greatly bent as having an inflectionpoint 50 in the vicinity of the side portion 2 c of the belt. By greatlybending the belt in trough shape, the residues adhering to the belt sideportions can be effectively removed without a decrease in the pressingforce.

Even when the return belt has trough shape, the cutwater rollers 30 orthe scrapers 34 (see FIG. 9) may be independently provided, or thecutwater rollers 30 and the scrapers 34 may be arranged along thedirection in which the belt moves, so that the residues adhering to thebelt side portions can be effectively removed.

In the above case, since the cutwater and scraping at the belt sideportions in the width direction can be reliably carried out, waterreceivers 36 provided on the lower side of the conveyor may be installedonly at the center portion of the belt width over the entire conveyor.

Subsequently, an example of the air-cushion belt conveyor to which thepresent invention is applied will be described.

FIG. 10 is a side view showing an end portion of the air-cushion beltconveyor. The conveyor is configured such that the belt 2 curved intrough shape is floating due to an air pressure and moving inside a duct10. The belt 2 passes through an inside of the duct 10 and is suspendedin an endless state at both end portions through end pulleys 3, 4. Thebelt 2 moves around the end pulley 3, through a guide pulley 37, andthrough tension pulleys 38, 39 provided in opposition for guiding thebelt in U-shape and a tension pulley 41 including a counter weight 40provided between these pulleys 38, 39, and then returns to the inside ofthe duct 10.

In the vicinity of a portion of the belt 2 inverted at a circulating endportion of the end pulley 3, two belt cleaners 42 having plate-shapedscraper portions are provided for removing residues adhering to the belt2. Between the guide pulley 37 and the tension pulley 38, a waterwashing nozzle 43, a scraper (belt cleaner) 44, a press roller 45 forpressing the belt 2 from above, a press roller 46 for pressing the belt2 from below, a press roller 47 for pressing the belt 2 from above, anda scraper (belt cleaner) 48 are arranged in this order. Thereby, afterinversion, the cleaners 42 scrape the residues adhering to the belt 2,and thereafter, the residues adhering to the belt 2 are washed away andthe residues in an solidified state are fluidized by the water washingnozzle 43 and scraped by the following scraper 44. The belt 2 iswater-cut and dehydrated while snaking through the three press rollers45–47, and the residues pressed and thereby layered between the rollersand the belt are scraped by the following scraper 48.

Since the press rollers 45–47 are the conventional straight-line shapedrollers extending in the width direction of the belt 2, they might beinsufficient to remove the residues at the belt side portions.Accordingly, downstream of these rollers and before the duct 10 intowhich the belt 2 in trough shape moves, the residue removing means forthe belt side portions is provided as described below.

FIG. 11 is a perspective view showing main part of the residue removingmeans. FIG. 12 is a front view. FIG. 13 is a plan view. The residueremoving means is based on the above-mentioned principle in FIG. 8. Theresidue removing means is constituted by cutwater rollers 31 provided onboth side walls of a casing 49, and is installed in the state in whichthe belt side portions 2 are greatly curved so as to have the inflectionpoints 50. Specifically, a pair of mounting brackets 51 are provided inopposition on both side walls of the casing 49, and are each providedwith a U-shaped member 53 through an extended plate 52. Betweenhorizontal plates 53 a constituting the U-shaped member 53 andvertically opposed to each other, a shaft 54 is provided. A cutwaterroller 31 is rotatably provided on the shaft 54. The extended shaft 52bolted to a back-surface side of a vertical plate 53 b constituting theU-shaped member 53 extends toward the direction of the side wall of thecasing 49. The extended plate 52 is provided with horizontally elongatedholes 55 in the vertical direction. The extended plate 52 is fixed tothe mounting bracket 51 through the elongated holes 55 by means of boltsand nuts 56. Since the elongated holes 55 are horizontally long, thefixing position of the extended plate 52 is horizontally displaced byloosening the nuts, thereby causing the cutwater roller 31 to be movableclose to or away from the belt. Thereby, a stable pressing force to theside portion 2 c of the belt is obtained and the pressing force can besuitably adjusted. Besides, since the belt is curved by bending in theopposite direction to bending of the curved forward belt, the scrapingof the residues adhering to the belt side portions can be facilitatedand reliably conducted.

FIG. 14 is a plan view in the direction of arrows taken along lineXIV—XIV in FIG. 1. FIG. 15( a) is a cross-sectional view taken alongline XVA—XVA in FIG. 14 and FIG. 15( b) is a cross-sectional view takenalong line XVB—XVB in FIG. 14.

From the entrance-side pulley 3 to the entrance 5 a of the trough 5(FIG. 1), plural support roller trains 6, 60 are arranged as beingspaced from each other under the forward portion of the belt 2(upper-stage belt portion moving to the left in the Figure).

As shown in FIGS. 14 and 15, the support roller train 6 comprised ofeight rollers 59 as support elements arranged in the shape ofcircular-arc along the width direction of the belt, and the supportroller train 60 comprised of nine rollers 59 arranged in the shape ofcircular-arc along the width direction of the belt are alternatelyprovided. All the support roller trains 6, 60 are comprised of therollers 59 of the same configuration. The support roller train 6comprised of the eight rollers is configured such that each set of fourrollers 59 are arranged at the same pitch on the left side and on theright side with respect to the center of the belt in the widthdirection. The support roller train 60 comprised of nine rollers isconfigured such that one roller 59 is placed at the center of the beltin the width direction, and each set of four rollers 59 are arranged onthe left side and on the right side at the same pitch as the supportroller train 6 comprised of eight rollers. This follows that betweenadjacent support rollers 6, 60, gaps G between the rollers 59 arearranged so as not to be on straight lines as seen from the longitudinaldirection of the belt 2.

This reduces deformation of the belt by bending along the longitudinaldirection of the belt. The number of rollers of each support train isnot intended to be limited to eight or nine. The number of rollers maybe less than eight or more than nine. Nonetheless, it is preferable thatone train is comprised of more rollers 59, because the deformation bybending is more relieved, and the corresponding positions are increased.

The characteristic in which the gaps between the rollers are arranged soas not to be on the straight lines as seen from the longitudinaldirection of the belt 2 is applicable to support roller trains on anexit side of the trough 5, although this is not shown. Thischaracteristic is also applicable to the lower support roller trains 7provided below the return portion (lower-stage belt portion moving tothe right in FIG. 1). When the return portion of the belt 2 is flat andthe support roller train is comprised of flat rollers as shown in FIG.31, the deformation by bending need not be taken into account, but, insome cases, troughs of circular-arc cross-section are employed even onthe return belt. In such cases, the support roller trains 6, 60 may beemployed.

In the above embodiment, the support roller train of the sameconfiguration is arranged every other train, but the present inventionis not limited to this. For example, the support roller train of thesame configuration may be arranged every three or more trains. Thisfollows that the gaps between the rollers of three or more roller trainsare arranged so as not to be on straight lines. In extreme cases, thegaps between rollers of all the trains are arranged so as not to be onstraight lines as seen from the longitudinal direction of the belt.

For example, in a belt conveyor 61 shown in FIG. 16, respective supportroller trains 63 are configured such that the rollers of the same shapeequal in number are shifted at the same pitch. However, all the supportroller trains 63 are shifted from one another in the width direction ofthe belt 2 with respect to the center point of the belt 2 in the widthdirection. Although it is preferable that more rollers 59 are arrangedin one support roller train 63, five rollers 4 are arranged in onesupport roller train 63 for easier understanding. Assuming that sixsupport roller trains are arranged in the state in which each of thetrains is comprised of five rollers each having a length W of 220 mm,the positions of the rollers in adjacent support roller trains areshifted by d=44 mm in the width direction of the belt 2.

In the above embodiment, to make difference between the gaps G betweenthe rollers, the number and arrangement of the rollers of the same shapeare changed for each support roller train. But, the present invention isnot limited to this. The positions of the gaps G are made different bychanging the length W of the rollers. Nevertheless, in view ofmanufacturing cost, it is desirable to use the rollers of the sameshape.

In a belt conveyor 62 in FIG. 17( a), the support roller train as thefirst support member is replaced by a support sliding member train 66 inwhich sliding members 64 are arranged along the width direction of thebelt 2 and a support sliding member train 67 in which another slidingmembers 65 are arranged along the width direction of the belt 2. Thesliding members 64, 65 are so-called support elements, and are formed ofsynthetic resin or the like with small friction coefficient and highwear resistance, for example, super-polymer polyethylene. The materialof the sliding members can be selected from various kinds of materials.

For example, as shown in FIGS. 17( a) and 17(b), bar-shaped slidingmembers 64 extending in the longitudinal direction of the belt 2 may beused. Fixing brackets 64 a are provided on the sliding members 64. Asshown in FIGS. 17( a) and 17(c), it is possible to use cylindricalsliding members 65 with their center axes extending in the widthdirection of the belt 2. Alternatively, the resin may be molded into thecylindrical sliding members 65, or a resin layer may be formed on asurface of a metal cylinder or the like. The bar-shaped sliding members64 are C-shaped in cross-section as shown in the Figure. The bar-shapedsliding members 64 may be manufactured by forming a resin layer on asurface of a metal gutter of C-shaped cross-section. Alternatively, theresin may be molded in the shape of bar. When these sliding members 64,65 are used, it is necessary that the gaps G between the sliding membersof at least adjacent support sliding members be arranged so as not to beon the straight lines as seen from the longitudinal direction.

The bar-shaped sliding members 64 and the cylindrical sliding members 65may coexist in one support sliding member train, although this is notshown. In that case, the cylindrical sliding members 65 are continuouslyprovided so as to conform to the length of one bar-shaped sliding member64 in the longitudinal direction of the belt. Further, these slidingmembers and the support rollers may coexist. Moreover, the supportroller train and the support sliding member may coexist. In brief, it isimportant that the gaps G between the sliding members or the rollers bearranged so as not to be on the straight lines as seen from thelongitudinal direction of the belt.

FIG. 18( a) shows that a belt conveyor 82 provided with support slidingmembers 68, 69 having different shapes as the second support members. Asshown in FIGS. 18( a) and 18(b), one support sliding member 68 isplate-shaped and extends in the shape of circular-arc along the widthdirection of the belt 2 and along the longitudinal direction of the belt2. As shown in FIGS. 18( a) and 18(c), the other support sliding member69 is bar-shaped and extends in the shape of circular-arc in the widthdirection of the belt 2. The support sliding members 68, 69 are eachsubstantially C-shaped in cross-section. That is, by downwardly curvingthe side portion of the belt 2 in the lateral direction, the resistanceto the belt 2 can be reduced. The support sliding members 68, 69 areprovided with fixing brackets 68 a, 69 a on their rear side,respectively. FIG. 18( d) is a view in the direction of arrows takenalong line VID—VID in FIG. 18( a), and shows the bar-shaped supportsliding member 69. As seen from this direction, the shape of thebar-shaped support sliding member 69 is the same as that of theplate-shaped support sliding members 66.

The support sliding members 68, 69 may coexist on one belt conveyor 82as shown in the Figure, but the present invention is not limited to thisconfiguration. For example, one of the support sliding members 68, 69may be arranged to be spaced at prescribed intervals. Since thesesupport sliding members 68, 69 serve to support the belt continuously inthe width direction of the belt 2, the deformation by bending does notoccur because of the absence of the gaps G.

Alternatively, as shown in FIG. 19, both of or one of the two types ofsupport sliding members 68, 69, and part or all of the support rollertrains 6, 60, 63 and the sliding member trains 66, 67 may coexist alongthe direction in which the belt moves. Such a configuration serves tounbend the deformation of the belt by bending which is caused by thesupport roller trains or the sliding member trains. In this sense, it ispreferable that the support sliding member is placed as the supportmember closest to the entrance 5 a of the trough 5. Further, both of orone of the two types of support sliding members 68, 69 and theconventional support roller trains 206 (FIG. 30) may be combined.

The support sliding member, the support roller train, or the likeclosest to the trough 5 may be placed as spaced apart from the endportion of the trough 5. Nonetheless, as shown in FIG. 19, it ispreferable that the support sliding member 68 (or 69) is placed incontact with an entrance end of the trough 5. This can seal a space R ofcompressed air between the belt 2 and the trough 5 (see FIG. 19( b)) bythe support sliding member 68, and therefore, the belt 2 can be floatingwell. To this end, the support sliding member 68(or 69) may be placed incontact with an exit end of the trough 5. It should be appreciated that,to produce a satisfactory seal effect, a curvature of cross-section ofthe support sliding member 68 in contact with the entrance end of thetrough 5 is preferably set smaller than a curvature in cross-section ofthe trough.

FIG. 20 is a perspective view showing an example of the troughs 5 in thebelt conveyor 1 in FIG. 1. Inside the duct 10 of a circular pipe shapeforming a long carrying path, a curved forward trough 5 on a carryingside is suspended in the diametric direction of the duct 10, and on anupper surface of the forward trough 5, the forward belt 2 a is provided.An air-supply chamber 71 is provided at the center of the lower portionof the forward trough 5 in the carrying direction (longitudinaldirection of the trough). The forward trough 5 is provided withair-supply holes 70 at even intervals so as to communicate with thesir-supply chamber 71.

Products are loaded on the forward belt 2 a. The forward belt 2 a iscaused to float and move above the troughs 5 while forming an air layerbetween the troughs 5 and the belt 2 by air for air-cushion ejectedthrough the air-supply holes 70 from the air-supply chamber 71 andcarries the products to target position. The forward belt 2 a turns backat a terminal portion of the carrying path and becomes the return belt20 b, which floats and moves along the inner surface of the duct 10below the forward trough 5 by the air for air-cushion ejected throughthe air-supply holes (not shown) from the air-supply chamber 72 underthe duct 10.

A portion indicated by a solid line in FIG. 20 is the forward trough 5.Since the forward trough 5 forming the carrying path is long, aplurality of troughs 5 are joined in the longitudinal direction. Aconnecting portion A connects the troughs 5 in such a manner that endfaces of the troughs 5 are butted with each other with little gap, and abacking member 75 spanning over the end faces of both troughs isprovided on lower surfaces of the troughs and fixed by means of bolts,nuts, and the like as a fixing member.

A connecting portion B has a sliding structure obtained by connectingthe troughs with gaps 76 between these troughs so that one of thetroughs 5 is slidable along a guide plate 83. The sliding structure isformed as a labyrinth seal mechanism L as mentioned later.

FIG. 21 is a schematic view simply representing the connecting portionB, in which FIG. 21( a) is a plan view, FIG. 21( b) is a longitudinalsectional view at a portion where the air-supply chamber 71 is provided,and FIG. 21( c) is a side cross-sectional view.

As shown in FIG. 21( a), the center portion of one trough 57 a is formedto have a rectangular concave portion 78 and the other trough 57 b isformed to have a rectangular convex portion 79 to be fitted in theconcave portion 78.

The adjacent troughs 57 a, 57 b are placed in such a manner that theconvex portion 79 of the other trough 57 b is inserted into the concaveportion 78 of the one trough 57 a so that one of these troughs isslidable along the longitudinal direction. The convex portion 79 isfitted in the concave portion 78 substantially to a half depth, with thegaps 76 allowing for the required sliding amount of the trough, andminute gaps 77 a are each formed between a side face 78 a of the concaveportion 78 and a side face 79 a of the convex portion 79. Therefore, inthis state, a wide air passage (groove) 77 b is formed between a tip endface 79 b of the convex portion 79 and a back end face 78 b of theconcave portion 78 (center portion). Also, wide air passages 77 cperpendicular to the minute gaps 77 a are each formed between a tip endface 78 c of the one trough 57 having the concave portion 78 and a face79 c of the other trough 57 b which is opposed to the tip end face 78 c.

Under the troughs, a guide plate 83 which is entirely substantiallyU-shaped is suspended between the troughs 57 a, 57 b so as to coverthese gaps 76, 82.

Therefore, the gaps 76 entirely communicate with the wide air passage(groove) 77 b at the center portion and the minute gaps (minute airpassage) 77 a, and with outer wide air passages 77 c. From the entirestructure of the gaps 76, this can be called a labyrinth groove 76. Thatis, the labyrinth seal mechanism L is formed. The leakage of the air forair-cushion supplied from the air-supply chamber 71 to the air passage(groove) 77 b at the center portion through the air-supply passage 70 iseffectively suppressed by the minute gaps 77 a. Since the minute gap 77a is formed by the side face 78 a of the concave portion 78 and the sideface 79 a of the convex portion 79, which are parallel to the directionin which the trough slides, the cross-sectional area of the gap 70 adoes not substantially change irrespective of the sliding of the trough,and hence, slight air leakage amount does not change.

By locating the minute gaps 77 a inwardly of the belt end faces 2 c,leakage of the air for air-cushion is suppressed. That is, as shown inFIG. 21( b), the air for air-cushion ejected from the air-supply holes70 forms the air layer between the trough 5 and the belt 2 a, andescapes from the minute gap between the upper surface of the trough 5and the belt end face 2 c while floating the belt 2 a. So, by locatingthe minute gaps 77 a slightly inwardly of the belt end faces 2 c in viewof snaking movement of the belt 2 a, the leakage of the air can beeffectively prevented.

FIG. 22( a) and FIG. 22( b) are a side cross-sectional view and a rearview in the case where the guide plate 83 is also provided with theair-supply chambers 73. A U-shaped guide plate 83 is provided so as toclose the labyrinth groove 76 from the rear side of the trough 5, thusforming the labyrinth groove 76 as described above.

The trough 57 b on the right side in the Figure is called a fixed side,i.e., the guide plate 83 and the trough 57 a are fixed by means of afixing member such as bolts and nuts. The left-side trough 57 a isslidably connected by means of the fixing member such as bolts and nutsthrough elongated holes 86 provided in the guide plate 83.

Specifically, as shown in FIG. 23( a), a stud bolt 85 is protruded fromthe lower surface of the trough 57 a by welding, and loosely fitted intoan elongated hole 86 provided in the guide plate 83 (or large-diameterhole) long in the direction in which the trough 57 a moves, and a nut 88is screwed to the stud bolt 85 through a washer 87 spanning theelongated hole 86 (or large-diameter hole).

Or, as shown in FIG. 23( b), a flush dent hole 89 is formed on thetrough 57 a side, a flush bolt 90 is fitted into the hole 89, a head ofthe flush bolt 90 protrudes from the elongated hole 86 (orlarge-diameter hole) provided in the guide plate 83, and a nut 88 isscrewed to the flush bolt 90 through the washer 87.

As shown in FIG. 22, an air-supply chamber 71 is provided under thetrough 5. The guide plate 83 is also provided with the air-supplychamber 73 and has an air-supply hole 74 communicating with an airpassage of the air-supply chamber 73. Between the air-supply chamber 71of the trough 57 b and the air-supply chamber 73 of the guide plate 83,a hose or a pipe 84 is provided to allow these chambers to communicatewith each other. Thereby, the air for air-cushion is also supplied tothe air passage (groove) 76 of the connecting portion between thetroughs. This ensures stable floatation of the belt at the connectingportion between the troughs. Although it is preferable that theair-supply chamber 73 of the guide plate 83 is connected to theair-supply chamber 71 of the fixed trough 57 b, this may be connected tothe air-supply chamber 71 of the sliding trough 57 a by means of anextensible/compressive hose.

FIG. 24 shows an example in which the slide structure having thelabyrinth seal mechanism is structured into multiple stages forincreasing the sliding amount of the trough. FIG. 24( a) is a sidecross-sectional view, and FIG. 24( b) is a rear view. The same referencenumerals as those in FIGS. 20 to 22 are used to identify the same orcorresponding parts, which will not be further described.

When a large sliding amount (for example, approximately 60 mm in total)is intended to be absorbed at one connecting portion, a large gap isrequired at the connecting portion between the troughs, which causesinsufficient air for air-cushion, thereby resulting in unstable movementof the belt.

FIG. 24 shows an example in which a trough 58 a provided with convexportions 81 on both sides and a trough 58 b provided with concaveportions 81 on both sides are interposed between the left trough 57 aand the right trough 57 b in the example in FIG. 22, thereby forming amulti-staged sliding structure. The connecting portions having thesliding structure are each provided with the labyrinth seal mechanism L.The air-supply chamber 71 is provided under each trough, and theair-supply chambers 71 are interconnected by means of a hose or a pipe84 a. It should be appreciated that the guide plate 83 may be providedwith the air-supply chamber connected by means of the hose or the pipeas shown in the example in FIG. 22 for the purpose of compensating forinsufficient air for air-cushion at the connecting portion.

As a matter course, the sliding structure having the labyrinth mechanismof the present invention is applicable to the return trough in the duct10 in FIG. 20, a trough of an air-cushion conveyor of a double cylindershape, or a trough of an air-cushion conveyor comprising a pair of ducts(reciprocating pipe) in the vertical direction.

FIG. 25 is a perspective view showing a guide member in FIG. 1.

In FIG. 1, the shoot 8 is provided above the belt 2 between theentrance-side pulley 3 and the trough entrance 5 a. The shoot 8 isinclined slightly forwardly (toward the direction in which the belt 2moves) from vertical. The shoot 8 may be vertically provided. A lowerend of the shoot 8 has an opening 8. The guide member 103 is mounted toa rear portion of the opening 8 a. The guide member 103 and the shoot 8constitute the loading device 101 for loading the products on the belt2. In this case, the shape of the opening in the lower end of the shoot8 may be, for example, an ellipse other than rectangle.

FIG. 25 shows a detail of the guide member 103. The guide member 103 hasa trapezium-shaped bottom plate 104 inclined forwardly and downwardly,and side plates 105 vertically provided on both sides of the bottomplate 104. The bottom plate 104 is inclined more greatly than the shoot8. With this configuration, the product dropping through the inside ofthe shoot 8 reaches the bottom plate 104 and is then loaded on the belt.The trapezium-shaped bottom plate 104 has a width decreasing toward itsfront. Therefore, by substantially conforming the center of a front edgeof the bottom plate 104 to the center of the belt in the widthdirection, the products are gathered to the center of the belt andevenly distributed in the right and left direction from the centercorresponding to a crest of mountain, so that uneven distribution of theproducts in the width direction of the belt can be avoided. Areinforcement rib 104 is provided on a lower surface of the bottom plate104.

A flange portion 107 provided with elongated holes 106 for mountingbolts is provided on an upper end side of the side plate 105. Ascorresponding to the elongated holes 106, flange portions 108 and boltholes (not shown) are provided on both sides of the lower end of theshoot 8. With this structure, the guide member 103 is mounted so as tobe displaceable in the front and rear direction (longitudinal directionof the belt 2) with respect to the opening 8 a of the shoot 8. Theelongated holes may be formed in the flange portions 108 of the shoot 8and the bolt holes may be formed in the flange portions 107 of the guideplate 103. This results in long elongated holes. As a result, the guidemember 103 can be displaceable within a long range. The both side plates105 are configured to have an upper end conforming to sides of therectangular opening 8 a, and hence extend outwardly and upwardly.

As shown in FIG. 26, in accordance with the guide member 103 (FIG. 26(a)), even the products dropping in an unevenly distributed state in thewidth direction through the inside of the shoot 8 (FIG. 26( b)) are inlarge part loaded on the belt 2 from the front edge of the bottom plate104 having a small width. That is, since the both side plates 105 extendoutwardly and upwardly as described above, the products dropping throughthe inside of the shoot 8 in a dispersed state are naturally gathered tothe center portion (FIG. 26( c)). Therefore, most of the products aregathered to the center portion of the belt 2 in the width direction(FIG. 26( d)), and are evenly distributed laterally. In addition to thefront opening 103 a of the guide plate 103, a front portion 8 b of theopening 8 a of the shoot 8 serves as an exit for the products from theshoot 8. Therefore, even when a great many products are dropping, theshoot 8 does not get clogged.

FIG. 27 shows a case where a center line of a cross-section of the shoot8 does not conform to a center line of the guide member 103. It is mostdesirable that the longitudinal center line of the guide member 103conform to the center line of the belt 2. Nonetheless, more often thannot, the longitudinal center line of the installed shoot 8 somewhatdeviates from the center line of the belt 2. The guide member 103 iseasily mounted to such a shoot 8 so as to conform to the center line ofthe belt 2. That is, as shown in the Figure the flange portion 107 ofthe guide member 103 and the flange portion 108 of the shoot 8 may beextended so as to offset the above deviation, and then overlapped witheach other. In this case, it is preferable that the opening 8 a of theshoot 8 is located in the guide member 103.

A loading device 111 in FIG. 28 is configured such that a plurality ofguide members 103 are mounted to the opening 102 a of the lower end ofthe shoot 102 along its longitudinal direction. Since the longitudinaldimension of the opening 102 a of the lower end of the shoot 102 islarger than that of the shoot 8 in FIG. 1, the structure and shape ofthe guide members 103 are configured to be identical to those in FIG.25. Therefore, each guide member 103 is longitudinally displaceable withrespect to the opening 102 a of the lower end of the shoot. Referencenumeral 118 denotes a flange portion of the shoot 102. The descriptionof the other details are omitted. It should be noted that, according tothe longitudinal dimension of the opening 102 a of the lower end of theshoot 102, the guide members having a smaller longitudinal dimension maybe installed. It is preferable that in the loading device 111, adistance D is set between adjacent guide members 103 as shown in theFigure for the purpose of larger area of the opening 102 a of the shoot.Also, instead of the above arrangement of the guide members, the heightof the lower ends of the plurality of guide members may decrease as theyare away from the front. To be specific, to prevent the products beingloaded from the guide member located behind from abutting with the lowerend of the guide member located in front, the lower end of each guidemember is set slightly higher than that of the guide member locatedadjacently and behind.

In accordance with the loading device 111, even when a great manyproducts drop or the products drop in a dispersed state, all the guidemembers 103 are capable of gathering these to the center of the belt 2.

In the loading device 113 in FIG. 29, a shoot 114 has a circular-arccross-section. A guide member 115 is shaped suitably for the shoot 114.To be specific, the guide member 115 is obtained by longitudinallydividing in two a tube of a cone with head cut off (a frustum of acone). In other words, the bottom plate and the side plate arecontinuously and integrally curved. Therefore, the guide member 115 hasa horizontal cross-section of a circular-arc shape. The averagecurvature of the circular-arc cross-section is set larger toward acarrying path face (the average curvature radius is smaller). And, theguide member 115 is mounted to the rear portion of the lower end of theshoot 114 in a downwardly and forwardly inclined condition. As a result,the circular-arc of the upper end edge of the guide member 115 becomesdifferent from the circular-arc of the lower end edge of the shoot 114.Therefore, non-conformity occurs in the connecting portion between theguide member 115 and the shoot 114, and the resulting gap can be easilyclosed by flange portions 116, 117.

According to the guide member 115, since the products are loaded on thebelt 2 from the front end edge having a small curvature radius, most ofthe products are gathered to the center portion of the belt 2 in thewidth direction.

The guide member 115 is shaped with the frustum of the conelongitudinally divided in two. The frustum of the cone is not limited tobe divided in two but, may be cut along a face including two radiusesforming a desired angle such as 120°, 150°, or 210° from the center ofthe frustum of the cone. Alternatively, a frustum of an elliptical conemay be cut in the manner described above.

In the above-mentioned loading devices 101, 111, 113, the guide members103, 115 are mounted to the shoots 8, 114, respectively, but the presentinvention is not limited to this configuration. For example, the guidemember may be mounted to the duct 10 or the skirt 9 so as to beposition-adjustable. In this state, the shoot may be installed such thatits lower end somewhat enters the inside of the guide member. Bymounting the guide member to the duct 10 or the skirt 9 so as to conformto the center line of the belt 2, there arises no problem regardless ofnon-conformity between the center line of the cross-section of the shoot8 and the center line of the belt 2 as described above (FIG. 27).

The present invention is applicable to any other belt conveyors as wellas the air-cushion belt conveyor. Further, the present invention isapplicable to conveyors other than the belt conveyor.

In accordance with the present invention, the friction resistancebetween the side portion of the belt and the trough can be greatlyreduced while ensuring the space for the compressed air for air-cushionbetween the belt and the trough. As a result, equipping cost andoperation cost of the belt conveyor can be reduced and life of the beltcan be prolonged.

In addition, in accordance with the present application, the residuesare removed independently only at the belt side portions. So, theresidues can be effectively removed without being affected by thedeformation of the belt and reduction of the pressing force.

Since the cutwater and scraping at the belt side portions in the widthdirection can be reliably conducted, the dropping water or powderreceivers (water receivers) can be installed only at the center portionof the belt in the width direction under the conveyor, and therefore canbe installed in a narrow space.

Further, the deformation of the belt by bending can be reduced orprevented, and the belt can be sufficiently floated without an increasein an air pressure.

Still further, the leakage amount of the air for air-cushion can bereduced, and the amount of air supply can be reduced. Because ofstabilized amount of air leakage, the belt can float stably and themoving resistance can be reduced. The width of the air passage at thelabyrinth portion becomes constant regardless of change in the gapbetween the troughs by providing the labyrinth seal mechanism at theconnecting portion between the troughs. As a result, since the leakageamount of the air for air-cushion becomes constant, the belt can be keptfloating stably and moving with reduced resistance.

Moreover, in the conveyor such as the belt conveyor, uneven distributionof the products can be prevented, and snaking of the carrying path suchas the belt can be prevented.

1. A trough of an air-cushion belt conveyor, the belt conveyor beingprovided with interconnected troughs, wherein the troughs have a slidingstructure with a gap between the troughs so as to be slidable in theirlongitudinal direction, and a labyrinth seal mechanism capable ofpreventing change in leakage amount of air for an air-cushion regardlessof change in the gap due to sliding of the trough is provided at aconnecting portion between the troughs.
 2. The trough of an air-cushionbelt conveyor according to claim 1, wherein at the connecting portionbetween the troughs, the troughs are fitted at their concave and convexportions with a gap in a direction in which the trough slides, therebyforming the sliding structure, and minute gaps parallel to the directionin which the trough slides are created during sliding of the trough,thereby forming the labyrinth seal mechanism.
 3. The trough of anair-cushion belt conveyor according to claim 2, wherein the minute gapsconstituting part of the labyrinth seal mechanism are provided inwardlyof belt side portions.
 4. The trough of an air-cushion belt conveyoraccording to claim 1, wherein the sliding structure having the labyrinthseal mechanism is provided in multiple stages in the longitudinaldirection of the troughs.
 5. A trough of an air-cushion belt conveyor,the belt conveyor being provided with interconnected troughs, whereinthe troughs have a sliding structure with a gap between the troughs soas to be slidable in their longitudinal direction, and a seal membercapable of preventing leakage of air for an air-cushion regardless ofchange in the gap due to sliding of the trough is provided at aconnecting portion between the troughs, and wherein a guide plate isprovided at the connecting portion between the troughs, for guidingmovement of the trough, the guide plate being provided with anair-supply chamber for supplying air for air-cushion and an air-supplyhole through which a gap for permitting sliding communicates with theair-supply chamber.
 6. The trough of an air-cushion belt conveyoraccording to claim 5, wherein the guide plate is fixed to one of thetroughs, and the other trough is slidably engaged with the guide platethrough an elongated hole or a large-diameter hole provided in the guideplate.
 7. The trough of an air-cushion belt conveyor according to claim1, wherein a guide plate is provided at the connecting portion betweenthe troughs, for guiding movement of the trough, and the guide plate isfixed to one of the troughs, and the other trough is slidably engagedwith the guide plate through an elongated hole or a large-diameter holeprovided in the guiding plate.